What 29 CFR 1926.1051 requires (plain English)
29 CFR 1926.1051 contains the general requirements of Subpart X (Stairways and Ladders). Its foundational rule is a means-of-access mandate: a stairway or ladder must be provided at all personnel points of access where there is a break in elevation of 19 inches (48 cm) or more, and no ramp, runway, sloped embankment, or personnel hoist is provided. This is the trigger that requires safe access before any specific stairway or ladder rule applies.
The section also addresses capacity and redundancy of access. When there will be 25 or more employees using a point of access, or when a means of access serves simultaneous two-way traffic, the employer must provide a second point of access (for example, a double-cleated ladder or two separate ladders), so workers are not forced to pass each other or crowd a single ladder. This reduces the falls and collisions that occur at busy, single-access points.
1926.1051 works with the rest of Subpart X: the scope and definitions are in 1926.1050, the detailed stairway requirements in 1926.1052, the detailed ladder requirements in 1926.1053, and training in 1926.1060. The general requirements here establish WHEN access must be provided and the basic redundancy rules, while the following sections govern HOW the stairways and ladders must be built and used.